Timer 误区，及两种正确写法

 这里先贴出错误写法：

 

 package com.test;import java.util.Timer;import java.util.TimerTask;import android.app.Activity;import android.os.Bundle;public class TestTimer_Wrong extends Activity {Timer timer = new Timer();TimerTask task = new TimerTask(){public void run() { setTitle("hear me?");}}; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); timer.schedule(task, 10000); }}

 

 

TimerTask 里面直接做UI更新，没有在UIThread里面。与Java的EDT线程，是同一概念。

 

 

正确写法一　：　交由UI Thread处理。

 

import java.util.Timer;import java.util.TimerTask;import android.app.Activity;import android.os.Bundle;public class TestTimer extends Activity {Timer timer = new Timer();TimerTask task = new TimerTask(){public void run() { runOnUiThread(new Runnable(){@Overridepublic void run() {setTitle("hear me?");}}); }}; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); timer.schedule(task, 10000); }}

 

 

正确写法二　：由Handler处理UI　更新。

 

package com.test; import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.os.Message; public class TestTimer extends Activity { Timer timer = new Timer(); Handler handler = new Handler(){ public void handleMessage(Message msg) { switch (msg.what) { case 1: setTitle("hear me?"); break; } super.handleMessage(msg); } }; TimerTask task = new TimerTask(){ public void run() { Message message = new Message(); message.what = 1; handler.sendMessage(message); } }; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); timer.schedule(task, 10000); } }